I am using retrofit2 kotlinx serialization to deserialize the response. The json response look like something like this.

{
    "type": "ETA",
    "version": "1.0",
    "generated_timestamp": "2022-11-29T15:39:57 08:00",
    "data": [
        {
            "co": "KMB",
            "route": "91M",
            "dir": "I",
            "service_type": 1,
            "seq": 13,
            "dest_tc": "寶林",
            "dest_sc": "宝林",
            "dest_en": "PO LAM",
            "eta_seq": 1,
            "eta": "2022-11-29T15:52:21 08:00",
            "rmk_tc": "",
            "rmk_sc": "",
            "rmk_en": "",
            "data_timestamp": "2022-11-29T15:39:44 08:00"
        },
        {
            "co": "KMB",
            "route": "91M",
            "dir": "I",
            "service_type": 1,
            "seq": 13,
            "dest_tc": "寶林",
            "dest_sc": "宝林",
            "dest_en": "PO LAM",
            "eta_seq": 2,
            "eta": "2022-11-29T16:06:39 08:00",
            "rmk_tc": "原定班次",
            "rmk_sc": "原定班次",
            "rmk_en": "Scheduled Bus",
            "data_timestamp": "2022-11-29T15:39:44 08:00"
        },
        {
            "co": "KMB",
            "route": "91M",
            "dir": "I",
            "service_type": 1,
            "seq": 13,
            "dest_tc": "寶林",
            "dest_sc": "宝林",
            "dest_en": "PO LAM",
            "eta_seq": 3,
            "eta": "2022-11-29T16:21:39 08:00",
            "rmk_tc": "原定班次",
            "rmk_sc": "原定班次",
            "rmk_en": "Scheduled Bus",
            "data_timestamp": "2022-11-29T15:39:44 08:00"
        }
    ]
}

I try parsing with this model.

@Serializable
data class MarsPhoto(
    val type: String = "", //The corresponding API that returns the data
    val version: String = "",//The version number of the JSON returned.
    val generated_timestamp: String = "",//The timestamp of the initial generated time of the response before it is cached.
    val data: Eta
)

@Serializable
data class Eta(
    val co:String ="KMB",//The bus company
    val route: String = "", //The bus route number of the requested bus company
    val dir: String = "",//The direction of the bus route
    val service_type: String = "",//The service type of the bus route.
    val seq: Int = 0, //The stop sequence number of a bus route
    val dest_tc: String = "",//The destination of a bus route in Traditional Chinese
    val dest_sc: String = "",//The destination of a bus route in Simplified Chinese.
    val dest_en: String = "",//The destination of a bus route in English
    val eta_seq: Int = 0,//The sequence number of ETA
    val eta: String = "-",//The timestamp of the next ETA
    val rmk_tc: String = "",//The remark of an ETA in Traditional Chinese
    val rmk_sc: String = "",//The remark of an ETA in Simplified Chinese.
    val rmk_en: String = "",//The remark of an ETA in English
    val data_timestamp: String = "",//The timestamp of the data when it was initially
)

but an exception occur!

FATAL EXCEPTION: main                                                                                                 Process: com.example.marsphotos, PID: 17692                                                                                                   kotlinx.serialization.json.internal.JsonDecodingException: Expected start of the array '[', but had 'EOF' instead at path: $
                                                                                                    JSON input: .....heduled Bus","data_timestamp":"2022-11-29T16:30:16 08:00"}]}

May i get some help

CodePudding user response：

From what I see in your json response, you receive an array of Eta objects.

So, you may try to rewrite your classes to:

@Serializable
data class MarsPhoto(
    val type: String = "", //The corresponding API that returns the data
    val version: String = "",//The version number of the JSON returned.
    val generated_timestamp: String = "",//The timestamp of the initial generated time of the response before it is cached.
    val data: Data
)
@Serializable
data class Eta(
    val co:String ="KMB",//The bus company
    val route: String = "", //The bus route number of the requested bus company
    val dir: String = "",//The direction of the bus route
    val service_type: String = "",//The service type of the bus route.
    val seq: Int = 0, //The stop sequence number of a bus route
    val dest_tc: String = "",//The destination of a bus route in Traditional Chinese
    val dest_sc: String = "",//The destination of a bus route in Simplified Chinese.
    val dest_en: String = "",//The destination of a bus route in English
    val eta_seq: Int = 0,//The sequence number of ETA
    val eta: String = "-",//The timestamp of the next ETA
    val rmk_tc: String = "",//The remark of an ETA in Traditional Chinese
    val rmk_sc: String = "",//The remark of an ETA in Simplified Chinese.
    val rmk_en: String = "",//The remark of an ETA in English
    val data_timestamp: String = "",//The timestamp of the data when it was initially
)

@Serializable
data class Data( val data: List<Eta>)

CodePudding user response：

Try this

@Serializable
data class MarsPhoto(
    val type: String = "", 
    val version: String = "",
    val generated_timestamp: String = "",
    val data: List<Eta> = emptyList()
    )